While incredible medical advancements in chemotherapeutics development for cancer treatment have been made, the majority of these are not selective in their mechanism of action, leading to adverse effects. Given the systemic toxicity associated with these therapies, they are not well suited for long-term use. Natural health products, or NHPs, may provide a way to selectively target the oxidative and metabolic vulnerabilities in cancer cells. White tea (Camelia sinensis) and rosemary (Salvia rosmarinus) are two natural extracts that have been studied extensively for their medicinal properties. However, their anticancer activity and mechanism of action are yet to be fully elucidated. We have examined the extracts’ cancer cell-killing ability as well as their interactions with common chemotherapeutics in MDA-MB-231 cells, a triple-negative breast cancer cell line, in vitro. Cell death measurement, morphological and biochemical characterization of apoptotic cell death, mechanisms of action (mitochondrial depolarization and oxidative stress), and immunofluorescence assays to estimate the percentage of cancer stem cells (CSCs) were performed following treatment with Synthite tea extract (STE) and rosemary extract (RE), provided by Synthite Industries Limited alone and in combination with cisplatin and paclitaxel. The key findings in this study are that STE and RE alone demonstrated very efficient anticancer activity against TNBC, and more importantly, the administration of the extracts in conjunction with cisplatin and paclitaxel sensitizes cancer cells to achieve enhanced cell death. In addition, CSCs were found to be sensitive to treatment with STE alone and in combination with RE and exhibited greater sensitivity to combination therapies compared to chemotherapeutic alone. The significance of these observations is that STE and RE, well-tolerated NHPs, have the potential to enhance the efficacy of current chemotherapeutics when combined, as well as prevent relapse for TNBC.

中文翻译：

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绿茶叶和迷迭香提取物选择性诱导三阴性乳腺癌细胞和癌症干细胞死亡，并增强常见化疗药物的疗效

虽然癌症治疗化疗药物的开发取得了令人难以置信的医学进步，但其中大多数药物的作用机制没有选择性，从而导致不良反应。考虑到与这些疗法相关的全身毒性，它们不太适合长期使用。天然保健品（NHP）可能提供一种选择性针对癌细胞氧化和代谢脆弱性的方法。白茶（Camelia sinensis）和迷迭香（Salvia rosmarinus）是两种天然提取物，其药用特性已被广泛研究。然而，它们的抗癌活性和作用机制尚未完全阐明。我们在体外检查了提取物的癌细胞杀伤能力以及它们与 MDA-MB-231 细胞（一种三阴性乳腺癌细胞系）中常见化疗药物的相互作用。在使用 Synthite 茶提取物 (STE) 和迷迭香提取物 (RE)，由 Synthite Industries Limited 单独提供以及与顺铂和紫杉醇组合提供。这项研究的主要发现是，单独使用 STE 和 RE 对 TNBC 具有非常有效的抗癌活性，更重要的是，将提取物与顺铂和紫杉醇联合使用可以使癌细胞变得敏感，从而增强细胞死亡。此外，发现 CSC 对单独使用 STE 以及与 RE 联合治疗敏感，并且与单独化疗相比，对联合治疗表现出更高的敏感性。这些观察结果的意义在于，STE 和 RE 两种耐受性良好的 NHP，联合使用时有可能增强当前化疗药物的疗效，并预防 TNBC 复发。